diff --git a/ivas_processing_scripts/audiotools/__init__.py b/ivas_processing_scripts/audiotools/__init__.py
index 3d3955271905ab61a0196a1b0878063e20398d6b..37855e8d7302b9bbf50e354f151f195f6e1bc87c 100755
--- a/ivas_processing_scripts/audiotools/__init__.py
+++ b/ivas_processing_scripts/audiotools/__init__.py
@@ -227,7 +227,7 @@ def get_argparser():
 
 def main():
     parser = get_argparser()
-    
+
     args = parser.parse_args()
 
     # special arguments for listing formats
@@ -240,11 +240,13 @@ def main():
             else:
                 print(", ".join(fmt.keys()))
         exit()
-    
+
     # validate required arguments
     if args.input is None or args.in_fmt is None or args.output is None:
         parser.print_usage()
-        raise SystemExit("the following arguments are required: -i/--in, -if/--in_fmt, -o/--out")
+        raise SystemExit(
+            "the following arguments are required: -i/--in, -if/--in_fmt, -o/--out"
+        )
 
     elif args.input is not None:
         if not args.out_fs:
@@ -280,7 +282,9 @@ def main():
         else:
             # input was a dir so output should be a dir too
             if args.output.is_file():
-                raise NotADirectoryError(f"Input directory '{args.input}' specified with file output to '{args.output}' - please specify an output directory instead")
+                raise NotADirectoryError(
+                    f"Input directory '{args.input}' specified with file output to '{args.output}' - please specify an output directory instead"
+                )
             if not args.output.exists():
                 args.output.mkdir()
                 print(f"Created output directory {args.output}")
diff --git a/ivas_processing_scripts/audiotools/convert/osba.py b/ivas_processing_scripts/audiotools/convert/osba.py
index 26092e3a4f07e1bef8a24f62455a7bb22b024b95..c45850bda08c936dfbc90423ea77b231124a0c26 100644
--- a/ivas_processing_scripts/audiotools/convert/osba.py
+++ b/ivas_processing_scripts/audiotools/convert/osba.py
@@ -81,14 +81,14 @@ def convert_osba(
 
         # combine results
         try:
-            out.audio = out_ism.audio + out_sba.audio
+            out.audio = 0.5 * (out_ism.audio + out_sba.audio)
         except ValueError as e:
             if (
                 out_ism.audio.shape[0] != out_sba.audio.shape[0]
                 and out_sba.audio.shape[0] == osba.audio.shape[0]
             ):
-                out.audio = out_sba.audio
-                out.audio[: out_ism.audio.shape[0], :] += out_ism.audio
+                out.audio = 0.5 * out_sba.audio
+                out.audio[: out_ism.audio.shape[0], :] += 0.5 * out_ism.audio
             else:
                 raise e
 
@@ -104,7 +104,7 @@ def convert_osba(
         render_sba_to_cba(sba, out_sba)
 
         # combine results
-        out.audio = out_ism.audio + out_sba.audio
+        out.audio = 0.5 * (out_ism.audio + out_sba.audio)
 
     # OSBA -> SBA
     elif isinstance(out, audio.SceneBasedAudio):
@@ -118,7 +118,7 @@ def convert_osba(
         render_sba_to_sba(sba, out_sba)
 
         # combine results
-        out.audio = out_ism.audio + out_sba.audio
+        out.audio = 0.5 * (out_ism.audio + out_sba.audio)
 
     # OSBA -> OMASA
     elif isinstance(out, audio.OMASAAudio):
@@ -128,14 +128,15 @@ def convert_osba(
                 "OSBA to OMASA conversion only possible if number of ISM objects matches"
             )
 
-        # only render SBA part
+        # only render SBA part to MASA
         out_sba = audio.fromtype(out.name[4:])
         out_sba.metadata_file = out.metadata_files[-1]
         render_sba_to_masa(sba, out_sba)
 
-        out.audio = np.concatenate(
-            (osba.audio[:, : osba.num_ism_channels], out_sba.audio), axis=1
-        )
+        # ism audio is passed through
+        ism_audio = osba.audio[:, : osba.num_ism_channels]
+
+        out.audio = np.concatenate((ism_audio, out_sba.audio), axis=1)
 
     # OSBA -> OSBA
     elif isinstance(out, audio.OSBAAudio):
diff --git a/ivas_processing_scripts/audiotools/convert/scenebased.py b/ivas_processing_scripts/audiotools/convert/scenebased.py
index de7e39ae84ccd30ca7d9fda0490b7869534340ed..a2b4222641acefc566bfd5e3126298cdf6a55bad 100755
--- a/ivas_processing_scripts/audiotools/convert/scenebased.py
+++ b/ivas_processing_scripts/audiotools/convert/scenebased.py
@@ -35,7 +35,7 @@ from typing import Optional, Union
 from warnings import warn
 
 import numpy as np
-from scipy.special import lpmv
+from scipy.special import factorial, lpmv
 
 from ivas_processing_scripts.audiotools import audio
 from ivas_processing_scripts.audiotools.audioarray import delay, framewise_io
@@ -348,8 +348,8 @@ def getRSH(
     for i, (l, m) in enumerate(LM):
         # N3D norm
         response[i, :] = np.sqrt(
-            ((2 * l + 1) * float(np.math.factorial(l - np.abs(m))))
-            / (4 * np.pi * float(np.math.factorial(l + np.abs(m))))
+            ((2 * l + 1) * float(factorial(l - np.abs(m))))
+            / (4 * np.pi * float(factorial(l + np.abs(m))))
         )
 
         # trig term